Extreme ultraviolet photoresist and method

Abstract

Resist materials having enhanced sensitivity to radiation are disclosed herein, along with methods for lithography patterning that implement such resist materials. An exemplary resist material includes a polymer, a sensitizer, and a photo-acid generator (PAG). The sensitizer is configured to generate a secondary radiation in response to the radiation. The PAG is configured to generate acid in response to the radiation and the secondary radiation. The PAG includes a sulfonium cation having a first phenyl ring and a second phenyl ring, where the first phenyl ring is chemically bonded to the second phenyl ring.

What is claimed is: 
     
       1. A resist material with enhanced sensitivity to radiation, the resist material comprising:
 a polymer; 
 a sensitizer; and 
 a photo-acid generator (PAG) that includes a cation and an anion, wherein the cation of the PAG includes a sulfur chemically bonded to a first phenyl ring and a second phenyl ring, and further wherein the cation of the PAG further includes an additional chemical group chemically bonded to the first phenyl ring and the second phenyl ring. 
 
     
     
       2. The resist material of  claim 1 , wherein the polymer includes polyhydroxystyrene. 
     
     
       3. The resist material of  claim 2 , further comprising at least one hydroxyl (OH) group chemically bonded to the polyhydroxystyrene. 
     
     
       4. The resist material of  claim 1 , wherein the sensitizer includes polyhydroxystyrene. 
     
     
       5. The resist material of  claim 1 , wherein the first phenyl ring includes a first carbon and a second carbon adjacent to the first carbon and the second phenyl ring includes a third carbon and a fourth carbon adjacent to the third carbon, the first carbon of the first phenyl ring and the third carbon of the second phenyl ring are chemically bonded to the sulfur, and the second carbon of the first phenyl ring and the fourth carbon of the second phenyl ring are chemically bonded to the additional chemical group. 
     
     
       6. The resist material of  claim 5 , wherein the chemical group is a C1-C20 alkyl group, a cycloalkyl group, a hydroxyl alkyl group, an alkoxy group, an alkoxyl alkyl group, an acetyl group, an acetyl alkyl group, a carboxyl group, an alkyl caboxyl group, a cycloalkyl carboxyl group, a C2-C30 saturated hydrocarbon ring, a C2-C30 unsaturated hydrocarbon ring, a C2-C30 heterocyclic group, or a 3-D chemical structure. 
     
     
       7. The resist material of  claim 1 , wherein the anion is sulfonyl hydroxide. 
     
     
       8. The resist material of  claim 1 , wherein the anion is fluoroalky sulfonyl hydroxide. 
     
     
       9. The resist material of  claim 1 , wherein the sensitizer is chemically bonded to the polymer. 
     
     
       10. The resist material of  claim 1 , further comprising a blocking group chemically bonded to the polymer. 
     
     
       11. A resist material with enhanced sensitivity to radiation, the resist material comprising:
 a polymer; 
 a sensitizer configured to generate an electron directly from the sensitizer in response to the radiation; and 
 a photo-acid generator (PAG) configured to generate acid in response to the electron, wherein the PAG includes a sulfonium cation having a first phenyl ring and a second phenyl ring bonded to a sulfonium sulfur, wherein the first phenyl ring is further connected to the second phenyl ring through a chemical group separate from the sulfonium sulfur. 
 
     
     
       12. The resist material of  claim 11 , wherein the first phenyl ring includes a first carbon, the second phenyl ring includes a second carbon, and the sulfonium cation further includes a third carbon that is chemically bonded to the first carbon and the second carbon, such that the third carbon connects the first phenyl ring to the second phenyl ring. 
     
     
       13. The resist material of  claim 12 , wherein the sulfonium cation further includes at least one carbon chemically bonded to the third carbon. 
     
     
       14. The resist material of  claim 11 , wherein the first phenyl ring includes a first carbon, the second phenyl ring includes a second carbon, and the sulfonium cation further includes a third carbon chemically bonded to the first carbon and a fourth carbon chemically bonded to the second carbon, wherein the third carbon is chemically bonded to the fourth carbon, such that the third carbon and the fourth carbon connect the first phenyl ring to the second phenyl ring. 
     
     
       15. The resist material of  claim 14 , wherein the sulfonium cation further includes at least one carbon chemically bonded to the third carbon, at least one carbon chemically bonded to the fourth carbon, or both. 
     
     
       16. The resist material of  claim 11 , wherein the polymer, the sensitizer, or both have a polyhydroxystyrene chemical structure. 
     
     
       17. The resist material of  claim 11 , wherein the chemical group is an alkyl group with two or more carbons. 
     
     
       18. The resist material of  claim 11 , wherein the sensitizer is chemically bonded to the polymer. 
     
     
       19. A resist material with enhanced sensitivity to extreme ultraviolet (EUV) radiation, the resist material comprising:
 a polymer, wherein the polymer includes a poly(norbornene)-co-malaic anhydride (COMA) polymer, a polyhydroxystyrene (PHS) polymer, or an acrylate-based polymer; 
 a sensitizer configured to generate electrons upon absorbing the EUV radiation, wherein the sensitizer includes PHS, poly-fluorostyrene, or poly-chlorostyrene; and 
 a photo-acid generator (PAG) configured to generate acid upon absorbing the electrons, wherein the PAG includes a triphenylsulfonium-based cation that includes a first phenyl ring connected to a second phenyl ring. 
 
     
     
       20. The resist material of  claim 19 , wherein the triphenylsulfonium-based cation that includes the first phenyl ring connected to the second phenyl ring includes one of the following chemical structures: